For material development, crystal information such as crystal phase or crystal orientation is an important characteristic of the material that is related to their physical properties. There has been a number of crystal structure measurement systems proposed that uses electron beam diffraction patterns to identify the crystal information.
For example, JP 2003-121394 discloses an SEM equipped with electron back-scattered diffraction (EBSD) detector which uses electron diffraction pattern, known as Kikuchi pattern, to perform the crystal information analysis. JP 2003-121394 discloses a method to identify crystal phase and orientation with a use of crystal structure database that generates a set of estimated diffraction parameters to identify individual electron backscatter diffraction bands in the image dataset. By matching the observed electron backscatter diffraction bands with estimated diffraction parameters, the crystal information can be obtained. However, EBSD is a surface-sensitive method and it usually takes long time for the measurement depending on the crystal grain size. Also, EBSD cannot evaluate very tiny crystal grain size where mixing of nearby diffraction patterns occurs.
Another method, such as the one disclosed in JP H07-066253, uses SEM with more than one sample tilt or rotation condition. The maximum amount of back-scattered electrons signal among those sample tilt or rotation conditions, which is related to the penetration depth of the primary electrons, is used to determine the direction of crystal plane with respect to the direction of primary electrons. The different amount of back-scattered electron signal originating from different penetration depth of primary electrons provides image contrast which is known as channeling contrast.